"There will be a lot of movement, a lot of forces in transit," one Army officer said. "This raises serious force protection issues for us."

While recognizing these risks, American commanders in Iraq say proper planning could result in significant advantages that could help offset the dangers.

According to Pentagon and military officials, commanders are planning to take advantage of the overlap of arriving and departing soldiers, which offers a natural, if temporary, increase in troop strength without the politically contentious process of requesting additional forces.

Gen. John P. Abizaid, commander of American and coalition forces in the region, is said by senior Pentagon officials to be well into planning for new operations intended to help stabilize Iraq and to capture or kill anti-American fighters during the rotation period. Officers declined to discuss specific plans being considered.